1. Field of the Invention
The present invention relates to wireless communication and, more particularly, to a method of performing channel sounding in a wireless local area network system and an apparatus supporting the same.
2. Related Art
With the recent development of information communication technology, a variety of wireless communication techniques are being developed. From among them, a Wireless Local Area Network (WLAN) is a technique for wirelessly accessing the Internet at homes or companies or in specific service providing areas by using portable terminals, such as a Personal Digital Assistant (PDA), a laptop computer, and a Portable Multimedia Player (PMP), based on wireless frequency technology.
In existing WLAN systems supporting High Throughput (HT) and Very High Throughput (VHT), a WLAN system that may operate in a band of 1 GHz or less is being proposed unlike in systems using 20/40/80/160/80+80 MHz bandwidths of a 2 GHz band and/or a 5 GHz band. If a WLAN system operates in a band of 1 GHz or less, a channel having a very narrow bandwidth is used compared to existing WLAN systems. Accordingly, service coverage can be further extended compared to the existing systems.
Meanwhile, if a frequency band, that is, a basis for the operation of a WLAN system, is changed, the format of physical layer data unit suitable for the characteristics of a changed physical layer needs to be proposed. It is also required to propose a channel sounding method capable of providing support so that channel state information in a changed channel band is fed back.